One way that a wireless cellular service provider can improve the coverage provided by a given base station or group of base stations is by using a distributed antenna system (DAS). In a DAS, radio frequency (RF) signals are communicated between a host unit and one or more remote antenna nodes. A host unit is communicatively coupled to one or more base stations. For example, the host unit is directly connected to the base station using coaxial cabling or the host unit communicates with the base station wirelessly (that is, “over the air” or “on frequency”) using a donor antenna and a bi-directional amplifier (BDA). Down-link RF signals are received from the base station at the host unit. The host unit uses the down-link RF signals to generate a down-link transport signal for distributing to one or more of the remote antenna nodes. Each such remote antenna node receives the down-link transport signal and reconstructs the down-link RF signals from the down-link transport signal and causes the reconstructed down-link RF signals to be radiated from at least one antenna coupled to or included in that remote antenna node. A similar process is performed in the up-link direction. Up-link RF signals received at one or more remote antenna nodes are used to generate respective up-link transport signals that are transmitted from the respective remote antenna nodes to the host unit. The host unit receives and combines the up-link transport signals transmitted from the remote antenna nodes. The host unit reconstructs the up-link RF signals received at the remote antenna nodes and communicates the reconstructed up-link RF signals to the base station. In this way, the coverage of the base station can be expanded using the DAS. One or more intermediate devices (also referred to as “expansion hubs” or “expansion units”) can be placed between the host unit and the remote antenna nodes in order to increase the number of remote antenna nodes that a single host unit can feed and/or to increase the host-unit-to-remote-antenna-node distance.
In one type of DAS, multiple remote nodes are simulcast from a single base station sector. The DAS is deployed in a 1×N configuration, i.e., one host interface feeds N remote antenna nodes. When the air interface being deployed is some form of code division multiple access (CDMA), there is sometimes a need to broadcast CDMA pilot signals, known as “beacon” pilots, in addition to the pilots associated with the main traffic bearing channels. These beacon pilots can be used to assist in handoff of communication devices (such as handsets) from one base station sector to another, or to assist in mobile position determination.